Mengnan Li,Chengyu Gong,Guobin Ren,Xiaoyong Xu,Minghuang Hong,Zhong Li
Although plant virus disease is destructive for economic losses of agricultural production, few studies focus on the field of solid state of pesticides. Dufulin (DFL) is a novel plant antiviral agent with high efficiency but low solubility and is easy to agglomerate during the process of crystallization. In this paper, the polymorphism behavior of DFL was systematically studied. Five polymorphs (Forms I–IV and VI), a solvate (Form V) and an amorphous form were discovered and characterized by powder X-ray diffraction and thermal analytical methods. Single crystals of Forms I, III, IV, V, and VI were obtained and their structures were identified by single-crystal X-ray diffraction. Based on the results of stability experiments (solid-state stability and solvent-mediated transition), thermal analysis methods, solubility studies and powder dissolution experiments, Form I appeared to be the thermodynamically most stable phase with the lowest solubility under ambient conditions, closely followed by Form III. In addition, the relative stability of the different crystal forms was simulated by density functional theory. As the result, the thermodynamic order of different forms was as follows: I > III > II > IV > VI > V. It is the first time that seven crystalline forms of DFL are reported, which fills the blank of DFL in the crystal engineering field and prompts the development of the formulation.
Dongmei Wang,Xin Xie,Di Gao,Kai Chen,Zhuo Chen,Linhong Jin,Xiangyang Li,Baoan Song
Southern rice black-streaked dwarf virus (SRBSDV) causes disease in crops, which reduces the quality and yield. Several commercial antiviral agents are available to control the SRBSDV induced disease. However, the mechanism of antiviral agents controlling SRBSDV is largely unknown. Identifying targets in SRBSDV is a key step of antiviral agent discovery. Here, we investigated the potential protein target of the antiviral agent dufulin. We cloned and expressed a soluble viroplasmic P6 protein in the prokaryote Escherichia coli and the eukaryote Spodoptera frugiperda 9. The dissociation constants of dufulin with the purified P6 protein from E. coli and S. frugiperda 9 expression systems were 4.49 and 4.95 μM, respectively, indicating a strong binding affinity between dufulin and P6 protein. In vivo, dufulin significantly inhibited the expression of both P6 protein and P6 gene in the SRBSDV-infected rice leaves. This inhibition on P6 protein expression was also observed in transformed Nicotiana benthamiana where the P6 was overexpressed. Our data also showed that dufulin inhibited the duplication of SRBSDV in a dose-dependent manner in infected rice leaves with a half maximum effective concentration of 3.32 mM. It is therefore concluded that dufulin targets the viroplasmic protein P6 to inhibit the virulence of SRBSDV.
危险品化学品经营许可证（带存储）